Flash Flood Prediction Program

Time: 910 AM Tue May 4, 2021 Forecaster: Justin Brooks ------------------------- Heavy Precipitation Outlook Flash Flood Prediction Program ------------------------- WARMER TODAY WITH A CHANCE FOR SCATTERED AFTERNOON RAIN/ISOLATED THUNDERSTORMS - A more seasonable day today with partly cloudy skies before high temperatures reach the upper 50's to low 60's on the plains with temperatures around 50 degrees in the foothills this afternoon. - A disturbance moves in from the W/NW this afternoon resulting in scattered rain showers with isolated thunderstorms. Storms will initiate along the foothills around midday and move out onto the plains between 1-3pm with the best chance for storm activity through 8pm before rain shower chances taper off into the evening. Storm movement will be relatively quick, between 10-15mph helping limit point rainfall amounts. Typical rain showers/isolated thunderstorms will produce a TR-0.20" in 10-30 minutes with isolated higher amounts possible if a stronger storm can develop, or there is training of thunderstorms over a specific area. Some small hail and gusty winds will also be possible under storms that develop. - Skies will gradually clear into the evening with overnight lows in the upper 30's to low 40's across the plains. STORM RAINFALL POTENTIAL AND DURATION: Rain showers and weak thunderstorms will produce TR-0.2" in 10-30 minutes. A moderate to strong thunderstorms will have the potential to produce 0.2-0.4" in 10-30 minutes. WORST CASE SCENARIO: Training of moderate/strong thunderstorm cells may result in up to 0.8" of rain in 60-90 minutes. A LOOK AHEAD: W/NW flow aloft will continue into Wednesday bringing another slight chance for rain showers/isolated thunderstorms in the afternoon, with the threat for flooding remaining minimal at best. High-pressure moves in Thursday bringing much warmer temperatures in the 70's with mostly sunny skies. Even warmer Friday as highs expected to reach the low 80's with continued sunny and dry conditions. LOCATION PRIME TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams 100 PM TO 800 PM Trace (50%) to 0.2" (20%) to 0.4" (5%) NONE Arapahoe 100 PM TO 800 PM Trace (50%) to 0.2" (20%) to 0.4" (5%) NONE Boulder 100 PM TO 800 PM Trace (50%) to 0.2" (20%) to 0.4" (5%) NONE Broomfield 100 PM TO 800 PM Trace (50%) to 0.2" (20%) to 0.4" (5%) NONE Denver 100 PM TO 800 PM Trace (50%) to 0.2" (20%) to 0.4" (5%) NONE Douglas 100 PM TO 800 PM Trace (40%) to 0.2" (15%) to 0.4" (5%) NONE Jefferson 100 PM TO 800 PM Trace (40%) to 0.2" (15%) to 0.4" (5%) NONE Foothills above 6500ft       Boulder 100 PM TO 800 PM Trace (50%) to 0.2" (20%) to 0.4" (5%) NONE Douglas 100 PM TO 800 PM Trace (40%) to 0.2" (15%) to 0.4" (5%) NONE Jefferson 100 PM TO 800 PM Trace (40%) to 0.2" (15%) to 0.4" (5%) NONE MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]